Yakima Basin Water Supply - May Forecast

YAKIMA, Wash. – The Bureau of Reclamation’s May 2018 Total Water Supply Available forecast for the Yakima Basin indicates the water supply will fully satisfy senior and junior water rights this irrigation season.

“April’s water supply indicators—precipitation (192 percent of average), snowpack (near average), and reservoir storage (117 percent of average) are each very healthy right now,” said Chuck Garner, Yakima Project River Operations supervisor. “The Yakima Basin water supply for the 2018 season will be ample to meet demands this spring and summer.”

Reclamation will provide water supply forecasts monthly through July. Specific water delivery levels will not be determined until later in the year after reservoir storage begins to decline.

This forecast is based on flows, precipitation, snowpack, and reservoir storage as of May 1, along with estimates of future precipitation and river flows. Other future weather conditions that determine the timing of the runoff and the demand for water also are critical in determining streamflows, prorations, and the extent to which the reservoirs fill.

“The recent warm weather has brought on some early snowmelt and increased natural flows, both very normal for this time of year,” Garner said.

If spring precipitation and runoff are unfavorable, Reclamation still expects an adequate supply. Because longer term weather conditions can be unpredictable, Garner recommends water conservation always be considered by users in the Yakima Basin.

Reclamation is the largest wholesale water supplier in the United States, and the nation's second largest producer of hydroelectric power. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at https://www.usbr.gov and follow us on Twitter @USBR.